INTRODUCTION The tettigonioid family Phaneropteridae (often consid- ered as subfamily Phaneropterinae) contains about 2200 species (OSF2), nearly one third of all known bush- crickets. Like all tettigonioids, Phaneropteridae communi- cate acoustically to find a mate. But unlike most other bush-crickets, where the mute female approaches the singing male, in Phaneropteridae typically the female responds acoustically to male song. This may be one of the reasons why some phaneropterid species have very complicated song patterns (e.g. Walker et al., 2003). Only in some species of the genus Poecilimon have the females lost their ability to respond acoustically, and this is asso- ciated with interesting changes in morphology and behav- iour of males and females (Heller & Helversen, 1993; Stumpner & Heller, 1992). While most phaneropterid species are long-winged, Poecilimon belongs to a species-rich group of short- winged species, the subfamily Barbitistinae (or tribe Bar- bitistini). About 150 described forms of Poecilimon occur in Europe and West Asia, with their centre of distribution north of the Eastern Mediterranean. The phylogenetic relationships within Poecilimon are still unresolved, but probably the ability to respond acoustically was lost sev- eral times independently (Heller, 1990). Below the species of the Poecilimon heroicus-group are revised and their calling songs and evolutionary relation- ships described. Already in the first revision of Poe- cilimon Ramme (1933) grouped these species together. Evidence is presented that the loss of the acoustical females occurred within this group, in contrast to pre- vious studies of other species groups of Poecilimon, which are homogeneous in this respect (Heller & Leh- mann, 2004; Heller & Sevgili, 2005; Lehmann, 1998). The group is also interesting from another aspect. Bush-crickets produce their calling songs by stridulation using their fore wings. In Poecilimon and other short- winged members of the Barbitistinae this seems to be the only function of the tegmina, which therefore should be modified to optimise sound production. Despite being their only function, the size of the tegmina varies greatly. In some species they are of moderate size, in others small to very small and completely concealed under the pro- notum (e.g. Heller, 2004). In P. tschorochensis (includ- ing P. rammei), however, they are huge, covering – according to the description – nearly the whole abdomen. Details of the unusual song of this species are presented. MATERIAL AND METHODS We studied specimens preserved in the following collections: CH (followed by the specimen code) – Collectio Heller; HUZOM – Hacettepe Üniversitesi Zooloji Müzesi, Ankara, Tur- key; MSPU – Moscow State Pedagogical University, Moscow, Russia; ZIN – Zoological Institute, Russian Academy of Sci- ences, St. Petersburg, Russia; ZMHB – Museum für Naturkunde der Humbolt-Universität, Berlin, Germany; ZMUM – Depart- ment of Entomology, Moscow University, Moscow, Russia. Other material is deposited in ZMUH – Zoologisches Museum Universität Hamburg, Hamburg, Germany. Eur. J. Entomol. 103: 853–865, 2006 ISSN 1210-5759 Bioacoustics and systematics of the Poecilimon heroicus-group (Orthoptera: Phaneropteridae: Barbitistinae) KLAUS-GERHARD HELLER 1 , OLGA S. KORSUNOVSKAYA 2 ,HASAN SEVGILI 3 and ROUSTEM D. ZHANTIEV 2 1 Grillenstieg 18, 39120 Magdeburg, Germany; e-mail: Heller.volleth@t-online.de 2 Department of Entomology, Moscow Lomonosov State University, Vorobiovy Gory, Moscow 119992, Russia; e-mails: korsuno@aport.ru; zhantiev@mail.ru 3 Harran Üniversitesi, Fen-Edebiyat Fakültesi, Biyoloji Bölümü, Osmanbey Kampüsü, Sanliurfa, Turkey; e-mail: hsevgili@harran.edu.tr Key words. Orthoptera, Poecilimon, morphology, systematics, bioacoustics, Tettigonioidea, bush-crickets, communication system, evolution Abstract. The species of the Poecilimon heroicus-group occur around the Caucasus (from north-eastern Turkey to south-eastern Ukraine). We describe the diagnostic morphological characters of all these species and the male calling song of three of the four spe- cies. Based on this data the following phylogenetic relationship is derived (P. tschorochensis (P. tricuspis (P. heroicus, P. bifenes- tratus))). Within the genus Poecilimon, the species can be recognised by a relatively wide pronotum and large tegmina. In one species, Poecilimon tschorochensis Adelung, 1907 (type species of the monotypic genus Artvinia Karabag, 1962, syn. n.; P. rammei Miram, 1938, syn. n.), the tegmina are very large and the song has unusually low spectral components. This species produced di- syllabic echemes at intervals of about 10 s. In two other species of the group, P. heroicus and P. bifenestratus, the calling song of males consists of an uninterrupted dense sequence of long syllables (syllable duration around 0.5 s; ca. 1 syllable/s at 20°C). In these species the auditory spiracles are reduced in size in both sexes, and the females have extremely small tegmina and are unable to respond to the male song acoustically, which would be typical for Phaneropteridae. The change in communication from acoustically responding to mute females has not been previously documented within a group of closely related species. 853